Analog
In general, pertaining to data consisting of continuously variable physical quantities. IBM
In telecommunications, characterized by modifying a base carrier's alternating current frequency in some way, such as by
amplifying the strength of the signal or varying the frequency, in order to add information to the signal. An analog signal
can be represented as a series of sine waves. WIS
Backhaul
In networking, getting data to the network backbone (similar to the meaning of the term in the satellite communication
industry). For example, a telecommunications vendor might use the term to describe how its network switch can be used to
interconnect data from a backhaul T-1 line on which mobile and remote office users are connected to an Internet service
provider and the backbone of the Internet.
IBM
Bandwidth
The amount of data that can be transmitted in a fixed amount of time. For digital devices, bandwidth is usually expressed in
bits per second (bps) or bytes per second. For analog devices, bandwidth is expressed in cycles per second, or Hertz (Hz). WPD
Call Center
A call center is a central place where customer and other telephone calls are handled by an organization, usually with some
amount of computer automation. Typically, a call center has the ability to handle a considerable volume of calls at the same
time, to screen calls and forward them to someone qualified to handle them, and to log calls.
WIS
Cell Site
A standalone fully digital base station that supports the OpenSky communication protocol in the 800 MHz SMR and NPSAC
frequency bands. The Cell Site combines digital voice and data to provide wireless rates of 19.2 kbps. The Cell Site is housed
in a custom weatherproof enclosure that can accommodate a range of possible installations: pole, wall, or pad mounting. OPS
Compression
The process of eliminating gaps, empty fields, redundancies, and unnecessary data to shorten the length of records or blocks,
or any encoding to reduce the number of bits used to represent a given message or record. IBM
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DTE
Data Terminal Equipment: That part of a data station that serves as a data source, data sink, or both. DEC
Fleet Map
In a digital trunked radio system, the mapping of talk groups to organizational units with communication requirements so that
all and only those system users who need to communicate with each other are able to do so. In the OpenSky system, talk groups
are arranged in ordered sets of up to 16 called profiles, which are in turn arranged in ordered sets of up to 16 called
personalities. The fleet map of an agency or other organization using the radio system comprises the radio personalities
defined and activated for its users, each of whom is assigned a radio personality. The fleet map also includes system options
and features assigned at the talk group, profile, or personality level, such as emergency behavior and encryption.
GPS
Global Positioning System: A worldwide satellite navigational system formed by 24 satellites orbiting the earth and their
corresponding receivers on the earth. The GPS satellites continuously transmit digital radio signals that contain data
identifying the satellite's location and the exact time to the earth-bound receivers. Using signals from three satellites, GPS
can calculate the longitude and latitude of the receiver. Using four satellites, GPS can also determine altitude. WPD
IP
Internet Protocol: In the Internet suite of protocols, a connectionless protocol that routes data through a network or
interconnected networks and acts as an intermediary between the higher protocol layers and the physical network. IBM
Leased Line
A nonswitched telecommunication line, or one on which connections do not have to be established by dialing. IBM
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Microwave
Electromagnetic energy having a frequency higher than one gigahertz (GHz). Microwave signals propagate in straight lines and
are not refracted or reflected by ionized regions in the upper atmosphere. Microwave beams do not readily diffract around
barriers such as hills, mountains, and large human-made structures. The microwave band is well-suited for wireless
transmission of signals having large bandwidth.
WIS
NOC
Network Operations Center: The physical space from which a typically large telecommunication network is managed, monitored,
and supervised. The NOC coordinates network trouble, provides problem management and router configuration services, manages
network changes, allocates and manages domain names and IP addresses, monitors routers, switches, hubs, and UPS systems that
keep the network operating smoothly, manages the distribution and updating of software, and coordinates with affiliated
networks. WPD
PLL
Phase-Locked Loop: An electronic circuit that controls an oscillator so that it maintains a constant phase angle ("lock") on
the frequency of an input, or reference, signal. A PLL ensures that a communication signal is locked on a specific frequency
and can also be used to generate, modulate, and demodulate a signal, and to divide a frequency. PLL is used often in wireless
communications where the oscillator is usually at the receiver and the input signal is extracted from the signal received from
the remote transmitter. WPD
PSTN
Public Switched Telephone Network: The standard voice telephone system. DEC
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SLIP
Serial Line Internet Protocol: A framing protocol used to send IP data streams across a serial line; often used to send IP
data over dialup telephone lines. DEC
Spread Spectrum
A form of wireless communication in which the frequency of the transmitted signal is deliberately varied. This results in a
much greater bandwidth than with a nonvaried signal. WIS
UDP
User Datagram Protocol: Part of the TCP/IP protocol suite, a protocol that provides unreliable, connectionless datagram
service, enabling an application program on one machine or process to send a datagram to an application program on another
machine or process. UDP uses Internet Protocol (IP) to deliver datagrams. IBM
UTC
Coordinated Universal Time: The time scale, based on the Systeme International (SI) second, as defined and recommended by the
Comite Consultatif International de la Radio (CCIR) and maintained (using an atomic clock) by the Bureau International des
Poids et Mesures (BIPM). For most practical purposes, UTC is equivalent to the mean solar time at the prime meridian (0
degrees longitude) of Greenwich, England, which is known as Greenwich mean time. UTC is sometimes called Z time or Zulu time.
IBM
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Footnotes
DEC Comer, Douglas E. Internetworking With TCP/IP: Principles, Protocols, and Architectures (4th
Edition). Prentice-Hall, Inc., 2000.
IBM IBM Corporation. Glossary of Computing Terms.
<http://publib.boulder.ibm.com/infocenter/eserver/v1r3s/index.jsp?topic=/iphav/iphwglos.htm> IBM Corporation, 1999.
OPS M/A-COM OpenSky Network. "Cell Site." <http://www.OpenSky.com> M/A-COM, Inc.
WPD Webopedia. <http://www.pcwebopedia.com/> Jupiter Media Corporation, 2003.
WIS WhatIs. <http://whatis.techtarget.com/> TechTarget.com, Inc., 2000.
